A 30-Second Preview of OnScreen DNA Replication
Firefox users go see it on YouTube
The short demo above was made from screen capture of OnScreen DNA Replication running in an iPad simulator. The actual speed of the app running on an iPad is greater.
The app had been paused well into the simulation. When it resumes in the movie, construction of the leading daughter strand continues with the addition of six more DNA nucleotides.
Then the action shifts to the other strand, the lagging strand, where construction of a second Okazaki fragment begins with primer RNA. All of the terms used in this description are fully explained in the text available in popover views of the app.
The DNA strands are also represented linearly with GATC nitrogenous base identifiers below the model. Strand elongation can be seen there, and the functioning of the original DNA strands as templates for daughter strand construction is clearly indicated.
The replisome (big blue oval) and its component enzymes (smaller ovals inside: DNA polymerase III and primase in the reactions shown) which bring about the polymerization are represented there also, moving along the strands to indicate where they are acting.
Commentary available in the app explains what is happening in every phase.
Hopefully, this brief look can give you a feel for how our simple model can be used to show in detail the essential steps taking place in DNA replication in an understandable, memorable, and enjoyable way.
